1. Field of the Invention
The present invention relates to a spray apparatus for spraying oily confectionery raw material which is capable of optionally controlling the spray area while keeping the particle size of sprayed particles and automatically controlling a spraying area and the particle size of sprayed oily confectionery raw material, in order to uniformly coating the raw material such as chocolate, white chocolate and oily cream onto the surface of food.
2. Description of the Related Art
Two methods for spraying the oily confectionery raw material have been known: an air spraying method using the compressed air for spraying the oily confectionery raw material and an airless spraying method in which the oily confectionery raw material is sprayed through a nozzle by use of a pressure tank or a high pressure pump. In the method for spraying the oily confectionery raw material using the compressed air, the amount or the pressure of compressed air is varied in order to control the spraying area and the particle size of the sprayed particles. When the amount or the pressure of compressed air is varied, the spraying area and the particle size are both changed. Therefore, the method is hard to control the spraying area and the particle size independently. In the airless spraying method in which the pressure tank or the high pressure pump is used for spraying, there is a method in that the liquid pressure supplied to a nozzle is varied to control the spraying area. In this case, the variation of the spraying area entails the variation of the particle size. Therefore, this method is also hard to control the spraying area and the particle size independently.
As described above, the air and airless spraying methods cannot meet the demand in this field., viz., they are hard to control the spraying area and the particle size independently. Meanwhile, the particle size is generally reduced when the spraying area is increased. Accordingly, a method in which the spraying area can be varied while keeping the particle size has been required.
In the airless spray method, in order to control the spraying area and the particle size of sprayed particles, it is necessary to control the pump pressure of the high pressure pump, to select a nozzle chip and to control the viscosity of the oily confectionery raw material. In the air spray method, in order to control them, it is necessary to control the pressure of the spraying pressured air, to control the viscosity of the raw material supplied to the nozzle and to control the amount of the providing raw material. Accordingly, the complexed adjustment, that is, the spraying area and the particle size are required to be controlled by the above complexed controls.